2 July 2018

Time to shed the ‘fad diet’ stigma?

Clinical Nutrition Obesity

Meal-replacement products found in many pharmacies are a safe and effective method of losing weight, new research shows, and clinicians have been urged to familiarise themselves with the options. 

Griffith University researchers have published an evaluation that supports meal replacements for long-term weight loss, saying doubts about the products’ efficacy were not founded. 

Analysing Pharmacy Guild data from around 22,000 individuals who participated in a weight-loss program for up to three years, the Griffith team found promising results. 

By replacing most of their meals with shakes and meal bars and high-protein meals, the group averaged an 8.5% peak drop in BMI at six months. Of the 800 who remained in the program for two years, the average weight loss was 4%.

The program incorporates meal replacements with personalised pharmacy support, a CSIRO-developed recipe book and online support tools.

Obesity expert Professor John Dixon is a proponent of very low calorie diets (VLCD) in the form of meal replacements.  

Legitimate meal replacements, such as Optifast, Optislim, Proslim and KicStart, included all the micro- and macronutrients a human body needed, and did not appear to cause any nutritional deficiencies, Professor Dixon said.

While there might be misconceptions that this approach was inferior to lifestyle or medication and surgery, Professor Dixon said the last two decades of research backed the safety and efficacy of meal replacments for weight loss.

“I use them in my standard practice and they are very successful,” the head of clinical obesity research at the Baker Heart and Diabetes Institute said. 

“The average person loses about 15% of their body weight over the three months, and then you taper them off it.”

Those who needed to lose more weight could use them for longer, he said, giving the example of one patient who had lost around 100 kilograms.

These patients might then transition down to using the meal replacments for one or two meals a day, or choose to restart a more intensive total meal-replacement regimen over the years if they noticed their weight creeping back up, he said. 

What made these meal replacements such a powerful tool was that patients lost their hunger after the first few days. VLCDs were low in carbohydrates, which put the body in a state of ketosis, and ketones suppressed the appetite, Professor Dixon said.

Some of his patients would be prescribed phentermine as an appetite suppressant for the first few days until the hunger naturally dropped off, he said. 

But meal replacements didn’t need to be used alone and were often best used in combination with medication, surgery or both. 

“What I find with drugs and VLCDs is that they’re enablers,” he said. 

“They actually help people stick to the diet they are on, because they don’t get hungry, they don’t feel out of control, they feel comfortable, and they don’t feel like they are being deprived.” 

If GPs had a patient interested in using a meal replacement, Professor Dixon recommended enlisting the help of a dietician experienced with overweight and obese patients. 

Typically, an intensive total meal replacement would be recommended for young or middle-aged adults with a BMI over 30, but might be appropriate for patients with a BMI of 27 or higher with health complications from the weight, such as diabetes.   

On the other hand, it might not be appropriate for people who had type 2 diabetes and needed insulin because it could precipitate hypoglycemia, patients who’d had a stroke or heart attack, those who’d had gallstones but had not had their gallbladder removed and women who were pregnant, breastfeeding and trying to become pregnant. 

Professor Dixon also said that the rapid weight loss might exacerbate gout in some patients.

But ultimately, he said it was a myth that rapid weight loss was more likely to lead to rapid weight gain. 

“If you lose weight slowly you are probably going to put it on slowly, if you lose weight rapidly you’re probably going to put it on slowly,” he said.